Q: The LED light on the sensor of my garage door opener is flashing?
A: (safety sensors: sensors located at the bottom corners of door that keep door from closing when door opening is obstructed.) The small LED lights on the sensor itself sometimes are located on the side of sensor or can be above or below the lense or eye part of sensor. One sensor is a transmitting light and the other is a receiving sensor. Sensors are located at the bottom right and left hand side of door track.
A blinking sensor light has 4 reasons to blink. 1) There is something blocking one sensor from seeing the other sensor. 2) the sensor has been damaged or age has made it malfunction. 3) One or both sensors have been knocked out of alignment. Either by being hit or the bracket it is attached to is not attached properly. 4) Most sensor wire is attached to walls and ceilings with a staple gun. This makes it easy to damage wire insulation and the staple can make contact with the wire and short it out.
If a sensor is in pieces and obviously needs to be replaced. Check for storage items in garage Shovels, brooms etc.. that can block the infrared beam. See if a vehicle parked too close to sensor. Some sensors are attached to a bracket that can bend easily or screws that attach it to wall can come loose and make bracket loose its alignment. If the sensor wire is the problem than you would need a new sensor to test the wire. Unplug old sensor and plug in new sensor and dont worry about attaching wire to wall and ceilings yet. Attach new sensor where the blinking sensor was and see if the light goes steady. Then hit opener button to see if the opener will function properly. This means wire has a break or short somewhere.
If i had a nickle for everytime i showed up for a service call and the homeowner had a shovel, broom etc.. blocking sensor. Or they just moved in recently and a moving box in garage was just put too close to infrared beam. I would be a lot richer today.
If you can easily bend or adjust a sensor and blinking light goes steady you have fixed problem. The more storage items you have around the sensors will increase the chance of blocking sensor. If sensor is in pieces and is clearly broken. Than call a technician.